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level: Level 1

Questions and Answers List

level questions: Level 1

Question	Answer
poisoning result from ingesting botulism toxin produced by the bacterium clostridium botulinum	BOTULISM
Results in the gradual atrophy of skeletal muscle fibers and their replacement with connective tissue	MUSCULAR DYSTROPHY
Results from the degeneration of the receptors of acetylcholine on the postsynaptic membranes of skeletal muscles fibers	MYASTHENIA GRAVIS
has many peripherally located nuclei per muscle fiber	SKELETAL MUSCLE
ARRANGE THE FOLLOWING: (largest to smallest) I. whole muscle II. muscle fibers (cells) III. myofilament IV. myofibril V.muscle fasciculus	1, 5, 2, 4, 3
made up of many sacromeres	MYOFIBRIL
attached to filaments that form the M line	MYOSIN MYOFILAMENT
the _______ of the myosine molecule binds to an active site on G actin.	HEAD
during the depolarization phase of action potential, the permeability of plasma membrane to ____________.	NA+ INCREASES
during repolarization, of the plasma membrane, _____ move outside the cell	k+
Given these events: Choose the arrangement that lists the events in the order they occur following a single stimulation of a skeletal muscle fiber. (1) The sarcoplasmic reticulum releases Ca2+. (2) The sarcoplasmic reticulum takes up Ca2+. (3) Calcium ions diffuse into the sarcoplasm. (4) An action potential moves down the T tubule. (5) The sarcomere shortens. (6) The muscle relaxes.	413526
Given these events: choose the arrangement that lists the events in the order they occur at a neuromuscular junction. (1) Acetylcholine is broken down into acetic acid and choline. (2) Acetylcholine diffuses across the synaptic cleft. (3) An action potential reaches the terminal branch of the motor neuron. (4) Acetylcholine combines with a ligand-gated ion channel. (5) An action potential is produced on the muscle fiber's plasma membrane	3,2,4,5,1
Acetylcholinesterase is an important molecule in the neuromuscular junction because it	BREAKS DOWN ACTYLCHOLINE
Choose the arrangement that lists the events in the order they occur during muscle contraction. (1) Calcium ions combine with tropomyosin. (2) Calcium ions combine with troponin. (3) Tropomyosin pulls away from actin. (4) Troponin pulls away from actin. (5) Tropomyosin pulls away from myosin. (6) Troponin pulls away from myosin. (7) Myosin binds to actin.	2,3,7
With stimuli of increasing strength, which of these is capable of a graded response?	WHOLE MUSCLE
Considering the force of contraction of a skeletal muscle fiber, multiple- wave summation occurs because of	an increase in Ca2+ concentration around the myofibrils.
Which of these events occurs during the lag (latent) phase of muscle contraction?	Ca2+ binding to troponin
A weight lifter attempts to lift a weight from the floor, but the weight is so heavy that he is unable to move it. The type of muscle contraction the weight lifter is using is mostly	ISOMETRIC
Which of these types of fatigue is the most common?	PSYCHOLOGICAL FATIGUE
Choose the conditions that occur in both physiological contracture and rigor mortis. (1) low ATP levels (2) little or no transport of Ca2+ into the sarcoplasmic reticulum (3) release of cross-bridges (4) Na+ accumulation in the sarcoplasm (5) formation of cross-bridges	1, 2, 4, 5
Jerry Jogger’s 3-mile run every morning takes about 30 minutes. Which of these sources provides most of the energy for his run?	AEROBIC RESPIRATION
Which of these conditions would you expect to find within the leg muscle fibers of a world-class marathon runner?	NUMEROUS MITOCHONDRIA
Which of these increases the least as a result of muscle hypertrophy?	NUMBER OF FIBERS
Relaxation in smooth muscle occurs when	myosin phosphatase removes phosphate from myosin.
Compared with skeletal muscle, visceral smooth muscle	maintains about the same tension, even when stretched.
Which of these statements concerning aging and skeletal muscle is correct?	A loss of muscle fibers occurs with aging.